obj[1] *and* obj['foo']

Gerhard Häring gerhard.haering at gmx.de
Wed Aug 7 00:30:18 CEST 2002


* Travis Shirk <travis at pobox.com> [2002-08-06 22:11 -0000]:
> I'm trying to write a class that implements __getitem__(self, k),
> but I'd like to invoke the method with integer keys and string keys.
> Currently, I'm getting exceptions when I use string keys:
> 
> TypeError: sequence index must be integer
> 
> I'm subclassing list (python 2.2) so I understand why the *sequence* does
> not allow non-int keys, and I assume that if I subclassed dict the reverse
> type clash would occur.  
> 
> So, is there a way to "override" __getitem__ to accept both types of
> access?
 
Yes - from the PgResultSet class in the pyPgSQL sources:

def __getitem__(self, key):
    if type(key) is StringType:
        key = self.__class__._xlatkey[key]
    return self.baseObj[key]

If you're only targeting Python 2.2+ an isinstance(key, str) is a better
solution.

Gerhard
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reduce(lambda x,y:x+y,map(lambda x:chr(ord(x)^42),tuple('zS^BED\nX_FOY\x0b')))




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